[all-commits] [llvm/llvm-project] 5a1c18: Pre-commit tests

[Sander de Smalen via All-commits]

  Branch: refs/heads/users/sdesmalen-arm/srlt-fix-coalescer-the-sequel
  Home:   https://github.com/llvm/llvm-project
  Commit: 5a1c186a44e413416b0768a4707cbf1594faa83d
      https://github.com/llvm/llvm-project/commit/5a1c186a44e413416b0768a4707cbf1594faa83d
  Author: Sander de Smalen <sander.desmalen at arm.com>
  Date:   2025-01-07 (Tue, 07 Jan 2025)

  Changed paths:
    M llvm/test/CodeGen/AArch64/register-coalesce-update-subranges-remat.mir

  Log Message:
  -----------
  Pre-commit tests


  Commit: d30269f9318f0265ed9c9868b23b1eb13a42bbd9
      https://github.com/llvm/llvm-project/commit/d30269f9318f0265ed9c9868b23b1eb13a42bbd9
  Author: Sander de Smalen <sander.desmalen at arm.com>
  Date:   2025-01-07 (Tue, 07 Jan 2025)

  Changed paths:
    M llvm/lib/CodeGen/RegisterCoalescer.cpp
    M llvm/test/CodeGen/AArch64/register-coalesce-update-subranges-remat.mir

  Log Message:
  -----------
  [Coalescer] Consider NewMI's subreg index when updating lanemask.

The code added in #116191 that updated the lanemasks for rematerialized
values, checked if DefMI's destination reg had a subreg index.
This seems to have missed the following case:

  %0:gpr32 = MOVi32imm 1
  %1:gpr64 = SUBREG_TO_REG 0, %0:gpr32, %subreg.sub_32

which during rematerialization would have the following variables set:

  DefMI = %0:gpr32 = MOVi32imm 1

  NewMI = %3.sub_32:gpr64 = MOVi32imm 1   (rematerialized value)

When checking whether the lanemasks need to be generated, considering
whether DefMI's destination has a subreg index is insufficient, we should
look at DefMI's subreg index instead.

The added tests are a bit more involved, because I was not able to
reconstruct the issue without having some control flow in the test.
These tests come from actual reproducers.


  Commit: 912ab029cc730580b50d79db89a32bd26d2ecb2a
      https://github.com/llvm/llvm-project/commit/912ab029cc730580b50d79db89a32bd26d2ecb2a
  Author: Sander de Smalen <sander.desmalen at arm.com>
  Date:   2025-01-07 (Tue, 07 Jan 2025)

  Changed paths:
    M llvm/lib/CodeGen/RegisterCoalescer.cpp

  Log Message:
  -----------
  Update comment


Compare: https://github.com/llvm/llvm-project/compare/f9e3ada4c4a3...912ab029cc73

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